Conventional injection molds are utilized to manufacture a variety of molded articles. For example, certain injection molds are used to produce threaded molded articles, such as threaded plastic covers for bottles or other containers. These injection molds utilize threaded cores to form the threads in the molded articles.
At the end of a molding cycle, a variety of mechanisms can be utilized to remove the threaded molded articles from the corresponding threaded cores. The removal mechanism utilized, however, can depend upon the design of the molded articles.
For example, if the plastic material of the threaded molded article is substantially flexible or resilient, the removal mechanism can push the threaded molded article from the threaded core, such as by using a conventional stripper ring. Alternately, if the plastic material is not sufficiently flexible, the removal mechanism can unscrew the threaded molded article from the corresponding threaded core to minimize damage to the threads. For example, the removal mechanism can be configured as a hydraulically operated rack and stripper plate. Actuation of the hydraulically operated rack can rotate the threaded cores of the injection mold relative to the molded articles in order to decouple the threads of the cores from the corresponding threads of the molded articles. The mechanically actuated, mechanically timed stripper plate then ejects each threaded molded article from the corresponding threaded core.